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Someday Tobacco May Save Lives, Too

July 25, 1999

Developments to Watch

Someday Tobacco May Save Lives, Too

You may not be able to get blood from a stone, but you can get it from a tobacco leaf. Or at least researchers at the Energy Dept.'s Pacific Northwest National Laboratory in Richland, Wash., can. It's all a matter of tinkering with the plant's genes.

Pacific Northwest researchers have successfully transplanted the human genes for certain blood-clotting factors into tobacco plants, which were chosen because they are common and well-studied. Most clotting factors now are made from human blood plasma, but infectious diseases, such as hepatitis B and C, flu, and HIV, can be transferred in these products. The tobacco-produced clotting factors, says bioprocessing group manager Daniel Anderson, are not only safer, but obtainable at about one-tenth the cost. "One and a half tobacco plants would produce enough blood factor to treat one hemophilia patient for a year, and a world supply for wound healing could be produced in a few small greenhouses," Anderson says.

So far, Pacific Northwest scientists have developed tobacco-produced coagulation factor VIII, which is used for hemophilia treatments, and thrombin, a clotting enzyme that aids in healing wounds. The blood protein is extracted from the plant leaves and then purified. No animals or humans have been tested yet, and it will likely be several years before the blood factors are available for humans, Anderson says.Edited by Catherine ArnstReturn to top

Can Science Kill Your Appetite?

If you think the urge to overeat is all in your mind, you may be right. Researchers at the University of California at Irvine College of Medicine have discovered, in the brain, a receptor that is a major regulator of eating behavior. If a drug were developed to block that receptor, it might also block the urge to overeat, they theorize.

Reporting in the July 15 issue of Nature, the scientists say the receptor binds to a nervous-system chemical called melanin-concentrating hormone (MCH), known to regulate how much and how often people and animals eat. Olivier Civelli, professor of pharmacology at U.C. at Irvine and lead investigator, says previous studies have shown that removing MCH from animals causes them to be lean, while animals injected with high amounts of the hormone become obese.

The receptor for the hormone was isolated in rats lacking the MCH gene. Through a process of elimination, the scientists found the one receptor that binds to the hormone. They also found that the MCH receptors are located in the areas of the brain that control smell, taste, appetite, and feeding urges.

Civelli says a drug that blocks the receptor might be able to control overeating without causing serious side effects, because it would not interfere with other biological functions. However, he cautions that it could be 10 years or more before such a drug is available.Edited by Catherine ArnstReturn to top

These Chips Are Wired from Within

Transistors get tinier and tinier, yet chips grow ever larger. What gives? The chief culprit is wiring. Connecting all those switches takes a maze of wires, and their complexity is growing faster than transistors are shrinking.

Researchers at Hewlett-Packard Laboratories and the University of California at Los Angeles are cooking up a way for the chips to wire themselves. They envision chips that chemically assemble themselves from conductive molecules and tiny carbon-nanotube wires. "On chips today, the wires are not routed the way nature would like--but chemistry could take care of that," says HP researcher Philip J. Kuekes.

In the July 16 issue of Science, the team uncorks its first success: a so-called logic gate (pictured) that self-assembled from special molecules designed by J. Fraser Stoddart, a UCLA chemist. To simplify lab experiments, the molecules are sandwiched between big metal electrodes (the dots on the chip). While the prototype gate has millions of molecules, Kuekes says future versions will need no more than a dozen. The next goal, he says, is self-assembled nanowires. The result could be chips 1,000 times more powerful than today's--and microprocessors smaller than pinheads.By Otis Port; Edited by Catherine ArnstReturn to top